<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
    h2{color:blue}
    </style>
    <!--引入外部css样式文件-->
    <link rel="stylesheet" href="my.css">
</head>
<body>
<h1 style="color:blue">内联样式</h1>
<h1 style="color:red">内联样式</h1>
<h2>内部样式1</h2>
<h2>内部样式2</h2>

</body>
</html>